Suna Ekin Kali

Blue-green infrastructure (BGI) options are considered to be more sustainable practices for water management and bring a range of benefits over and above water management. Davidshall in Malmö, Sweden, has been used as a case area to assess the multiple benefits of implementing BGI, considering seven alternative BGI schemes systematically developed along two scales: naturalness (i.e. more/less engineered/complex) and spatial distribution (e.g. decentral vs. end-of-pipe). The baseline alternative was the existing situation. The Benefit Estimation Tool (B£ST) was used to carry out a socio-economic assessment. The overall benefits varied significantly (two orders of magnitude), depending on the BGI scheme implemented: the greatest values were associated with natural decentral, natural decentral/end-of-pipe, and engineered decentral/end-of-pipe alternatives, those including sub-surface and open dry detention, stormwater tree pits, and rain gardens. The three B£ST categories providing the greatest benefits were enhancing amenity, benefiting health, and reducing flooding. Cultural ecosystem services were provided by all alternatives, and two alternatives (natural decentral and natural decentral/end-of-pipe) also provided regulating ecosystem services. The study showed that amenity and health were the most significant benefits of BGI implementation, contrasting with the main aim of BGI implementation, which was stormwater management (water quality and flood protection).

The Schuylkill River Watershed in southeastern PA provides essential ecosystem services, including drinking water, power generation, recreation, transportation, irrigation, and habitats for aquatic life. The impact of changing climate and land use on these resources could negatively affect the ability of the watershed to continually provide these services. This study applies a hydrologic model to assess the impact of climate and land use change on water resources in the Schuylkill River Basin. A hydrologic model was created within the Structural Thinking Experiential Learning Laboratory with Animation (STELLA) modeling environment. Downscaled future climate change scenarios were generated using Localized Constructed Analogs (LOCA) from 2020 to 2040 for Representative Concentration Pathways (RCP) 4.5 and RCP 8.5 emission scenarios. Three regional land use change scenarios were developed based on historical land use and land cover change trends. The calibrated model was then run under projected climate and land use scenarios to simulate daily streamflow, reservoir water levels, and investigate the availability of water resources in the basin. Historically, the streamflow objective for the Schuylkill was met 89.8% of the time. However, the model forecasts that this will drop to 67.2–76.9% of the time, depending on the climate models used. Streamflow forecasts varied little with changes in land use. The two greenhouse gas emission scenarios considered (high and medium emissions) also produced similar predictions for the frequency with which the streamflow target is met. Barring substantial changes in global greenhouse gas emissions, the region should prepare for substantially greater frequency of low flow conditions in the Schuylkill River.